137 lines
3.4 KiB
C
137 lines
3.4 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* bare bones 'talk to modem' program - similar to 'cu -l $device'
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* inspired by mgetty's microcom
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*
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* Copyright (C) 2007 by Vladimir Dronnikov <dronnikov@gmail.ru>
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*
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* Licensed under GPLv2, see file LICENSE in this tarball for details.
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*/
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#include "libbb.h"
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int microcom_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int microcom_main(int argc, char **argv)
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{
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struct pollfd pfd[2];
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#define sfd (pfd[1].fd)
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char *device_lock_file = NULL;
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const char *s;
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const char *opt_s = "9600";
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unsigned speed;
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int len;
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int exitcode = 1;
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struct termios tio0, tiosfd, tio;
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getopt32(argv, "s:", &opt_s);
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argc -= optind;
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argv += optind;
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if (!argv[0])
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bb_show_usage();
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speed = xatou(opt_s);
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// try to create lock file in /var/lock
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s = bb_basename(argv[0]);
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if (!s[0]) {
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errno = ENODEV;
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bb_perror_msg_and_die("can't lock device");
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}
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device_lock_file = xasprintf("/var/lock/LCK..%s", s);
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sfd = open(device_lock_file, O_CREAT | O_WRONLY | O_TRUNC | O_EXCL, 0644);
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if (sfd < 0) {
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if (ENABLE_FEATURE_CLEAN_UP)
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free(device_lock_file);
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device_lock_file = NULL;
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if (errno == EEXIST)
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bb_perror_msg_and_die("can't lock device");
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// We don't abort on other errors: /var/lock can be
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// non-writable or non-existent
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} else {
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// %4d to make mgetty happy. It treats 4-bytes lock files as binary,
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// not text, PID. Making 5+ char file. Brrr...
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s = xasprintf("%4d\n", getpid());
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write(sfd, s, strlen(s));
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if (ENABLE_FEATURE_CLEAN_UP)
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free((char*)s);
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close(sfd);
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}
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// open device
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sfd = open(argv[0], O_RDWR);
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if (sfd < 0) {
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bb_perror_msg("can't open device");
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goto unlock_and_exit;
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}
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// put stdin to "raw mode", handle one character at a time
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tcgetattr(STDIN_FILENO, &tio0);
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tio = tio0;
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tio.c_lflag &= ~(ICANON|ECHO);
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tio.c_iflag &= ~(IXON|ICRNL);
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tio.c_oflag &= ~(ONLCR);
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tio.c_cc[VMIN] = 1;
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tio.c_cc[VTIME] = 0;
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if (tcsetattr(STDIN_FILENO, TCSANOW, &tio)) {
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bb_perror_msg("can't tcsetattr for %s", "stdin");
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goto unlock_and_exit;
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}
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/* same thing for modem (plus: set baud rate) - TODO: make CLI option */
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tcgetattr(sfd, &tiosfd);
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tio = tiosfd;
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tio.c_lflag &= ~(ICANON|ECHO);
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tio.c_iflag &= ~(IXON|ICRNL);
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tio.c_oflag &= ~(ONLCR);
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tio.c_cc[VMIN] = 1;
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tio.c_cc[VTIME] = 0;
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cfsetispeed(&tio, tty_value_to_baud(speed));
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cfsetospeed(&tio, tty_value_to_baud(speed));
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if (tcsetattr(sfd, TCSANOW, &tio)) {
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bb_perror_msg("can't tcsetattr for %s", "device");
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goto unlock_and_exit;
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}
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// disable SIGINT
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signal(SIGINT, SIG_IGN);
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// drain stdin
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tcflush(STDIN_FILENO, TCIFLUSH);
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printf("connected to '%s' (%d bps), exit with ctrl-X...\r\n", argv[0], speed);
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// main loop: check with poll(), then read/write bytes across
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pfd[0].fd = STDIN_FILENO;
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pfd[0].events = POLLIN;
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/*pfd[1].fd = sfd;*/
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pfd[1].events = POLLIN;
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while (1) {
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int i;
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safe_poll(pfd, 2, -1);
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for (i = 0; i < 2; ++i) {
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if (pfd[i].revents & POLLIN) {
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len = read(pfd[i].fd, bb_common_bufsiz1, COMMON_BUFSIZE);
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if (len > 0) {
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if (!i && 24 == bb_common_bufsiz1[0])
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goto done; // ^X exits
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write(pfd[1-i].fd, bb_common_bufsiz1, len);
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}
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}
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}
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}
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done:
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tcsetattr(sfd, TCSANOW, &tiosfd);
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tcsetattr(STDIN_FILENO, TCSANOW, &tio0);
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tcflush(STDIN_FILENO, TCIFLUSH);
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if (ENABLE_FEATURE_CLEAN_UP)
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close(sfd);
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exitcode = 0;
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unlock_and_exit:
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// delete lock file
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if (device_lock_file) {
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unlink(device_lock_file);
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if (ENABLE_FEATURE_CLEAN_UP)
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free(device_lock_file);
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}
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return exitcode;
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}
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